Middle Period Research Articles

Dynamic characteristics and evolution laws of underground brine in Mahai salt lake of Qaidam Basin during mining process

In the late stage of underground brine mining in salt lakes, the method of injecting fresh water is often used to extract the salt from the brine storage medium. This method of freshwater displacement breaks the original water–rock equilibrium and changes the evolution process of the original underground brine. To explore the mechanism of salt release in saline water-bearing media under conditions of relatively fresh lake water dissolution, this paper analyzes the changes in the chemical parameters of brine from 168 sampling points in the Mahai salt lake in the Qaidam Basin at three stages (before exploitation, during exploitation, and late exploitation) by correlation analysis, ion ratio analysis, and other methods and investigate the variations in porosity and the evolution laws of brine. The results show that the changes in the main ion content and brine mineralization during the exploitation process are small. The changes in Ca2+ content are significant due to the low solubility of calcium minerals, the precipitation of gypsum during the mixing process, and the adsorption of cations by alternating with Ca2+. Primary intergranular pore skeletons are easily corroded to form secondary pores, which increase the geological porosity. Na+ and Cl- are the dominant ions in the brine in the study area, but the concentration of Ca2 + decreased significantly under the influence of mining, by 41.7% in the middle period and 24.5% in the late period. The correlation between Ca2+ and salinity changes significantly in different mining stages, and the reason for the decrease of Ca2+ may be due to the influence of mineral dissolution, mixing, and anion-cation exchange. The porosity of the layer in the study area showed the opposite trend of Ca2+, and the porosity increased first and then decreased. The innovation of this paper lies in analyzing the reasons and mechanisms of the disturbance of artificial dissolution mining on stratum structure by comparing the hydrochemical characteristics and porosity of underground brine storage media in three different mining stages. The research in this paper provides a theoretical basis for the calculation of brine resource reserves and the sustainable development of underground brine in salt lake areas.

Some problems of research of the Yuan Dynasty copper red enamel porcelain (you’li-hong)

In the scholarly exploration of Chinese ceramic history, the Yuan Dynasty emerges as a pivotal era, distinguished by its remarkable advancements in porcelain artistry, culminating in the mastery of porcelain craft. This period is notably marked by the emergence and refinement of underglaze red porcelain, a quintessential embodiment of Yuan ceramic excellence. The inception of underglaze red porcelain, a technique entailing the application of copper-containing colorant to porcelain before overlaying it with a transparent glaze and firing at temperatures exceeding 1350°C in a reducing kiln atmosphere, is historically attributed to the Yuan Dynasty. This technique, which flourished subsequently during the Ming and Qing Dynasties, represents a significant evolution in ceramic art. Each Chinese dynasty contributed uniquely to the ceramic arts, with the Yuan Dynasty particularly enhancing the underglaze red porcelain technique during its middle and late periods, as evidenced by the sophisticated coloration in surviving artifacts. This study aims to thoroughly examine the underglaze red porcelain of the Yuan Dynasty, highlighting its artistic uniqueness and exceptional craftsmanship. The paper commences with an overview of the Yuan Dynasty’s historical context—its political, economic, and cultural landscape—setting the stage for a deeper understanding of the underglaze red porcelain’s development. This is followed by an exploration of the porcelain’s creation process, including material selection and firing methods, to underscore the intricacies of its craftsmanship. Furthermore, a detailed analysis of the artistic and decorative elements of the underglaze red porcelain will be undertaken, focusing on aspects such as form, design motifs, and glaze hues, to unpack its stylistic and aesthetic dimensions. The culmination of this paper will be an evaluation of the historical significance and artistic merit of the Yuan Dynasty’s underglaze red porcelain, offering insights into its enduring legacy and influence on subsequent ceramic traditions. Through this comprehensive investigation, the study not only enriches our understanding of the Yuan Dynasty’s ceramic artistry but also underscores the importance of preserving and promoting traditional Chinese ceramic heritage. Additionally, it provides a foundation for further scholarly inquiry and conservation efforts in the realm of ancient Chinese ceramics.

Cubitus varus deformity following paediatric supracondylar humeral fracture remodelling predominantly in the sagittal direction: A three-dimensional analysis of eighty-six cases.

Three-dimensional (3D) capacity for remodelling in cubitus varus deformity (CVD) after paediatric supracondylar humeral fractures (PSHFs) remains unelucidated. This study investigated remodelling patterns after PSHFs by examining 3D deformity distribution over time after injury. Computed tomography (CT) data of 86 patients with CVD after PSHFs were analysed. The 3D deformity angles in the sagittal, coronal, and axial directions were assessed and correlated with the duration between the age at injury and CT evaluation. For the subgroup analysis, we performed the same correlation analysis in a younger (< 8 years old) and an older group (≥ 8 years old); we categorized the duration into early (< 2 years), middle (≥ 2 to < 5 years), and late periods (≥ 5 years) and compared the deformity angles of each direction among the three groups. Sagittal deformity showed a moderate correlation with the duration of deformity (r = -0.54; P < 0.001), while coronal and axial deformities showed a negligible correlation. Sagittal deformity showed moderate correlations with the duration in the younger group (r = -0.62; P < 0.001) and weak correlations in the older group (r = -0.37; P = 0.091). In the sagittal direction, the deformity angle in the early period was significantly larger than those in the mid and late periods (P < 0.001). However, there were no significant differences among the three groups in the coronal and axial directions. Sagittal deformities in CVDs are capable of remodelling, especially in the early period and at a younger age, whereas coronal and axial deformities are less likely to undergo remodelling.

A Chalcolithic presence east of the Sea of Galilee: The earliest finds on Mt. Sussita

ABSTRACT The characteristics and settlement patterns of the Early–Middle Chalcolithic period (ca. 5,800– 4,700 cal bc) around the Sea of Galilee have hardly been studied so far. The regional diversity of Chalcolithic material culture and the fragmentary nature of the archaeological record hinder a broader understanding of socio-cultural processes in this area. Chalcolithic architecture and finds, excavated for the last 23 years under the Graeco-Roman city of Hippos on Mt. Sussita, provide a rare opportunity to delve into the characteristics of the Chalcolithic period east of the Sea of Galilee. The current paper presents these remains and discusses their typological traits, spatial distribution, and possible cultural attribution. The site represents one of the few non-Golan Chalcolithic occurrences in the region, and its finds suggest an Early–Middle Chalcolithic period dating.

Rapid Rhythm and Overambitious Objectives: The Dual Mismatch in Japan's Rising Process

On August 15, 1945, Japanese Foreign Minister Mamoru Shigemitsu signed the instrument of surrender, marking Japan's formal capitulation to the Allied forces. This surrender signaled the defeat of the Axis powers and effectively halted Japan's rising trajectory. Grounded in positional realism and the theory of strategic rhythm, this paper introduces a novel analytical framework to examine the discrepancies between strategic objectives and rhythm in Japan's rising process. Subsequently, the paper chronologically reviews Japan's historical ascent, utilizing this analytical lens to assess the alignment between Japan's early, middle, and late-stage strategic objectives with its comprehensive capabilities, as well as the congruence between objectives and strategic rhythm. The analysis suggests that Japan initially maintained a strategic equilibrium with appropriate objectives and rhythm. However, discrepancies emerged in the middle period between strategic objectives and rhythm, escalating to a misalignment between objectives and comprehensive capabilities in the later stages. This confluence of misalignments culminated in a "dual mismatch," ultimately interrupting Japan's rise.

Nanogranular nature of the CSH gel

Hydration of cementitious materials is accompanied by the formation of calcium hydrosilicates (CSH). Accordingly, the hydration process is completed in the early, middle and late periods, leading to the formation of two types of CSH phases: low density (LD) and high density (HD). Using the nanoindentation method, it was explained nanogranular nature of the CSH gel, which is due to the contact forces of the CSH gel particles for these phases.

Deciphering the core microbiota in open environment solid-state fermentation of Beijing rice vinegar and its correlation with environmental factors.

Rice vinegar is a worldwide popular cereal vinegar worldwide and is typically produced in an open environment, and the ecosystem of solid-state fermentation is complicated and robust. The present study aimed to reveal the shaping force of the establishment of the ecosystem of Beijing rice vinegar, the core function microbiota and their correlation with critical environmental factors. The experimental findings revealed the changes in environmental factors, major metabolites and microbial patterns during Beijing rice vinegar fermentation were obtained. The major metabolites accumulated at the middle and late acetic acid fermentation (AAF) periods. Principal coordinates and t-test analyses revealed the specific bacterial and fungal species at corresponding stages. Kosakonia, Methlobacterium, Sphingomonas, unidentified Rhizobiaceae, Pseudozyma and Saccharomycopsis dorminated during saccharification and alcohol fermentation and early AAF, whereas Lactococcus, Acetobacter, Rhodotorula and Kazachstania dominated the later AAF stages. Canonical correspondence analysis of environmental factors with core microbiota. Temperature and total acid were the most significant factors correlated with the SAF bacterial profile (Pediococcus, Weissella, Enterococcus and Kosakonia). Ethanol was the most significant factor between AAF1 and AAF3, and mainly affected Acetobacter and Lactobacillus. Conversely, ethanol was the most significant factor in the SAF, AAF1 and AAF3 fungi communities; typical microorganisms were Saccharomyces and Malassezia. Furthermore, the predicted phenotypes of bacteria and their response to environmental factors were evaluated. In conclusion, the present study has provided insights into the process regulation of spontaneous fermentation and distinguished the key driving forces in the microbiota of Beijing rice vinegar fermentation. © 2024 Society of Chemical Industry.

Pre-Mamom Pottery Producers in the Heart of the Yucatan Peninsula

Recent research in the Maya Lowlands has revealed substantial new evidence for the first pottery producers at about 1000-600 bc, during the early Middle Preclassic period. This comparatively late adoption is a special case in Mesoamerica, where pottery appeared elsewhere up to a millennium earlier. Although archaic lifeways had long been established in the region, and pottery technology was likely known to some archaic communities, these new data reveal the complex set of circumstances that prompted the shift to ceramic production across the Yucatan Peninsula, Peten, and Belize. This article reviews these data from the perspective of the upland region of central and southern Yucatan, known as the Elevated Interior Region (EIR). Its rather complex early settlement links the EIR to contemporary pottery industries throughout the peninsula, suggesting well-established exchange systems were in place even as the first populations chose to settle more permanently on the landscape. Most significant among these cultural shifts was the increasing dependence on maize foodways as a primary subsistence strategy. Intensive maize agriculture has not been documented in Mesoamerica much before 1000 BC, yet ceramic technology was adopted independent of its use in other areas. Current evidence suggests, however, that the two were linked in the Maya Lowlands, where a relatively rapid transition took place as horticultural communities became more dependent on maize crops, followed waterways to settle more permanently on the landscape, and began producing pottery locally. 

A mathematical mould model for transient infiltration and lubrication behaviour of slag in a steel continuous casting process

The transient infiltration and lubrication behaviour of slag during continuous casting of steel is important for billet quality. A two-dimensional coupled mathematical mould model was developed to investigate these phenomena. The accuracy of the model was verified by comparing the calculated slag consumption with measurements by the plant. The results show that the liquid slag is consumed from the middle and late period of positive strip time to the next early period of positive strip time, including the entire negative strip time. The maximum downward infiltration velocity and positive pressure in the slag channel is at the middle of the negative strip time. Increasing the positive pressure of the slag channel is conducive to lubrication. The shear stresses acting on the shell surface and at the mould side were determined by the lubrication slag consumption and total slag consumption, respectively, and gradually decreased with increasing slag consumption. The negative strip time was lengthened to increase the slag consumption and prolong the time near the maximum downward shear stress, so as to be conducive to the demould.

Caches, Memory, and Ritual at the Maya City of Cival

Abstract This article examines Middle and Late Preclassic period ritual activity and caches discovered in the Central E Group complex at the ancient Maya site of Cival, which is located in northeastern Peten, Guatemala. It focuses on a series of excavations conducted in 2013 and 2014 at Structure 9, the E Group's western radial pyramid and uses theories of social memory and sacred place to provide insight into the recently discovered caches, termination rituals, and the deliberate destruction of architectural features found there. It also draws on previous ritual activity conducted in the Central E Group plaza and the site's broader history to obtain a more comprehensive understanding of the role of this complex as a sacred place and hub of memory at Cival for more than 1,000 years.

Three de novo assembled wild cacao genomes from the Upper Amazon

Theobroma cacao, the chocolate tree, is indigenous to the Amazon basin, the greatest biodiversity hotspot on earth. Recent advancement in plant genomics highlights the importance of de novo sequencing of multiple reference genomes to capture the genome diversity present in different cacao populations. In this study, three high-quality chromosome-level genomes of wild cacao were constructed, de novo assembled with HiFi long reads sequencing, and scaffolded using a reference-free strategy. These genomes represent the three most important genetic clusters of cacao trees from the Upper Amazon region. The three wild cacao genomes were compared with two reference genomes of domesticated cacao. The five cacao genetic clusters were inferred to have diverged in the early and middle Pleistocene period, approximately 1.83–0.69 million years ago. The results shown here serve as an example of understanding how the Amazonian biodiversity was developed. The three wild cacao genomes provide valuable resources for studying genetic diversity and advancing genetic improvement of this species.

Multiomics data integration, limitations, and prospects to reveal the metabolic activity of the coral holobiont.

Since their radiation in the Middle Triassic period ∼240 million years ago, stony corals have survived past climate fluctuations and five mass extinctions. Their long-term survival underscores the inherent resilience of corals, particularly when considering the nutrient-poor marine environments in which they have thrived. However, coral bleaching has emerged as a global threat to coral survival, requiring rapid advancements in coral research to understand holobiont stress responses and allow for interventions before extensive bleaching occurs. This review encompasses the potential, as well as the limits, of multiomics data applications when applied to the coral holobiont. Synopses for how different omics tools have been applied to date and their current restrictions are discussed, in addition to ways these restrictions may be overcome, such as recruiting new technology to studies, utilizing novel bioinformatics approaches, and generally integrating omics data. Lastly, this review presents considerations for the design of holobiont multiomics studies to support lab-to-field advancements of coral stress marker monitoring systems. Although much of the bleaching mechanism has eluded investigation to date, multiomic studies have already produced key findings regarding the holobiont's stress response, and have the potential to advance the field further.

Exhumation of the Qilian Shan and Miocene activity of the Haiyuan fault: insights from apatite (U–Th)/He thermochronology in the Laolongwan basin, northeastern Tibetan Plateau

The Tibetan Plateau, which is deformed by the collision between the Indian and Eurasian plates, is a natural laboratory in which to study intracontinental deformation related to northeastward growth of the plateau. However, how and when the Tibetan Plateau propagated to its present-day margins remain unclear. The Qilian Shan and Haiyuan fault, which serve as the topographic and geological boundaries of the high plateau, are key to revealing the uplift and expansion of the Tibetan Plateau. Here, we present detrital apatite (U–Th)/He and reverse modelling results from the Laolongwan basin, which is interpreted as a pull-apart basin controlled by activity of the Haiyuan fault in the east portion of the Qilian Shan region. Our results reveal three-stage tectono-thermal evolution of Qilian Shan: (1) Late Jurassic to Cretaceous rapid exhumation; (2) Late Cretaceous to middle Miocene tectonic quiescence period; and (3) exhumation after the middle Miocene. We suggest that the Jurassic to Cretaceous rapid exhumation might be related to the convergence of the Lhasa block with the Eurasian plate or regional extension during the Mesozoic closure of the Meso-Tethys, and the mid-Miocene accelerated exhumation was driven by Haiyuan fault activation related to the growth of the Tibetan Plateau to its northeastern margin. Supplementary material: Time–temperature paths of (U–Th)/He thermal history models (Fig. S1) and AHe age–depth relationship (Fig. S2) are available at https://doi.org/10.6084/m9.figshare.c.7018149 Thematic collection: This article is part of the Mesozoic and Cenozoic tectonics, landscape and climate change collection available at: https://www.lyellcollection.org/topic/collections/mesozoic-and-cenozoic-tectonics-landscape-and-climate-change

The oyster revolution: shell middens, shell temper, and settling down in North America’s Chesapeake region

Transformative social change occurred in the Chesapeake region with the intensification of oyster harvesting and the establishment of central places in estuarine settings at the outset of the Middle Woodland period (ca. A.D. 200). Accompanying the pivot toward estuarine living was the spread of shell-tempered ceramics indexing regional social networks from the Delaware Bay to the mouth of the Chesapeake Bay. Survey and excavation data from the Naval Weapons Station Yorktown (NWSY) on the York River trace this process on Virginia’s lower York River. Here, Middle Woodland populations established central places around the lower embayed portions of tidal creeks. Communal shell middens anchoring these central places offer evidence of intensive oyster harvesting and a history of periodic overharvesting, adjustment, and long-term sustainability. We hypothesize that common pool resource management, i.e., collective action and stewardship in the management of the oyster fishery, was an important part of Native societies’ settling down in this region.

Macro-Scale Population Patterns in the Kofun Period of the Japanese Archipelago: Quantitative Analysis of a Larger Sample of Three-Dimensional Data from Ancient Human Crania

The present study collected a larger set of three-dimensional data on human crania from the Kofun period (as well as from previous periods, i.e., the Jomon and Yayoi periods) in the Japanese archipelago (AD 250 to around 700) than previous studies. Three-dimensional geometric morphometrics were employed to investigate human migration patterns in finer-grained phases. These results are consistent with those of previous studies, although some new patterns were discovered. These patterns were interpreted in terms of demic diffusion, archaeological findings, and historical evidence. In particular, the present results suggest the presence of a gradual geological cline throughout the Kofun period, although the middle period did not display such a cline. This discrepancy might reflect social changes in the middle Kofun period, such as the construction of keyhole-shaped mounds in the peripheral regions. The present study implies that a broader investigation with a larger sample of human crania is essential to elucidating macro-level cultural evolutionary processes.

Chronological Trend of Opportunistic Endoscopic Screening for Gastric Cancer and Atrophic Gastritis.

Opportunistic endoscopic screening for gastric cancer was initiated in 2004 at our institute. We investigated chronological trends in gastric cancer detection rates based on individual characteristics and atrophic gastritis prevalence. Overall, 15,081 asymptomatic individuals aged ≥40 years without a medical history of gastric cancer underwent first-time esophagogastroduodenoscopy in our institute between February 2004 and December 2017. We retrospectively investigated individual characteristics and endoscopic diagnoses by period (early period: 2004-2007, middle period: 2008-2012, and late period: 2013-2017), clarified the long-term detection rate and the characteristics of endoscopic screening-detected gastric cancer, and evaluated the relationship between gastric cancer and atrophic gastritis. Gastric cancer detection rates in the early, middle, and late periods were 1.01% (76/7,503, men/women: 4,360/3,143, average age: 59.4 years, prevalence of atrophic gastritis: 72%), 0.69% (40/5,820, men/women: 3,668/2,152, average age: 56.8 years, prevalence of atrophic gastritis: 48%), and 0.46% (8/1,758, men/women: 1,083/675, average age: 58.7 years, prevalence of atrophic gastritis: 37%), respectively. Multivariate analysis revealed that male sex (odds ratio 1.92, 95% confidence interval 1.28-2.95), age ≥75 years (2.73, 95% CI 1.32-5.05), and atrophic gastritis (C1-C3: 2.21, 1.36-3.73, O1-O3: 5.36, 3.17-9.30) were significantly associated with the incidence of gastric cancer. The gastric cancer detection rate and atrophic gastritis prevalence have decreased over time. However, continuing endoscopic screening is important, especially for those at a high risk of developing gastric cancer complicated by severe atrophic gastritis.

Diaphyseal forearm fracture management in adolescent patients from 2011 to 2020: A multicenter study of surgery and regional anesthesia trends

BackgroundDiaphyseal forearm fractures are common traumatic injuries among children. There has been much debate on the use of intramedullary nailing (IMN) or plate fixation in the adolescent population (10–16 years of age). Furthermore, as ultrasound technology has advanced, the safety and efficacy of ultrasound-guided axillary brachial plexus block for children has dramatically improved. Therefore, anesthesia options for adolescent patients have increased in recent years. This study aimed to investigate recent surgical and regional anesthesia trends of diaphyseal forearm fractures in patients 10 to 16 years of age in Japan through a multicenter epidemiological survey from 2011 to 2020. MethodsThis retrospective, multicenter study included 226 pediatric patients with diaphyseal forearm fracture aged 10–16 years treated from January 2011 to December 2020. We divided the patients into four groups according to the period in which they were treated: early (2011–2013), middle (2014–2016), late (2017–2019), and COVID-19 (2020). Information from medical records was used to investigate the number of surgeries, types of anesthesia administered, and internal fixation methods used for diaphyseal forearm fracture in adolescent patients during each period. ResultsThe number of surgeries was generally constant in each period but decreased during the COVID-19 period. In the early, middle, late, and COVID-19 periods, the percentages of surgeries performed under regional anesthesia were 67.7, 85.5, 87.0, and 100% respectively (p = 0.003). During the same periods, the percentages of patients receiving IMN were 41.5, 49.3, 58.0, and 66.7%, respectively (p = 0.033). ConclusionThe use of IMN and regional anesthesia to treat diaphyseal forearm fracture in patients 10 to 16 years of age steadily increased during the study period from 2011 to 2020. These results indicate that regional anesthesia is safe, effective, and well-tolerated by adolescent patients. The treatment strategy for diaphyseal forearm fractures in adolescents using regional anesthesia in combination with IMN worked well and was effective during COVID-19. Our evidence suggests this trend will continue. We anticipate that our findings can be extrapolated for upper extremity fractures in adolescent patients beyond the Tokai region of Japan where the study was based.

Climate change projection using statistical downscaling model over southern coastal Iran

Iran is highly vulnerable to climate change, particularly evident in shifting precipitation and temperature patterns, especially in its southern coastal region. With these changing climate conditions, there is an urgent need for practical and adaptive management of water resources and energy supply to address the challenges posed by future climate change. Over the next two to three decades, the effects of climate change, such as precipitation and temperature, are expected to worsen, posing greater risks to water resources, agriculture, and infrastructure stability. Therefore, this study aims to evaluate the alterations in mean daily temperature (Tmean) and total daily rainfall (rrr24) utilizing climate change scenarios from both phases 5 and 6 of the Coupled Model Inter-comparison Project (CMIP5 and CMIP6, respectively) in the southern coastal regions of Iran, specifically north of the Strait of Hormuz. The predictions were generated using the Statistical Downscaling Model (SDSM) and National Centre for Environmental Prediction (NCEP) predictors, incorporating climate change scenarios from CMIP5 with Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5 and CMIP6 with Shared Socioeconomic Pathways (SSPs) 1, 2, and 5. The analysis was conducted for three distinct time periods: the early 21st century (2021−2045), middle 21st century (2046−2071), and late 21st century (2071− 2095). The results indicated that the CMIP5 model outperformed the CMIP6 model in simulating and predicting Tmean and rrr24. In addition, a significant increase in Tmean was observed across all the scenarios and time periods, with the most pronounced trend occurring in the middle and late 21st century future periods. This increase was already evident during the base period of 2021-2045 across all scenarios. Moreover, the fluctuations in precipitation throughout the region and across all scenarios were significant in the three examined future periods. In conclusion, the study reveals that the coastal area of Hormozgan province will experience rising temperatures and changing rainfall patterns in the future. The results indicated that among CMIP5 scenarios, RCP8.5 had highest changes of Tmean (+1.22 °C) in BL station in 2071-2095 period. The lowest change magnitude of Tmean among CMIP5 scenarios was found in RCP4.5 (–1.94 °C) in Ch station in 2046-2070 period. The results indicated that among CMIP5 scenarios, RCP8.5 had highest changes of rrr24 (+150.23 mm) in Ch station in 2071-2095 period. The lowest change magnitude of rrr24 among CMIP5 scenarios was found in RCP8.5 (–25.77 mm) in BA station in 2046-2070 period. These changes may lead to challenges such as increased water and energy consumption, heightened risks of droughts or floods, and potential damage to agriculture and infrastructure. These findings offer valuable insights for implementing local mitigation policies and strategies and adapting to emerging climate changes in Hormozgan's coastal areas. For example, utilizing water harvesting technologies, implementing watershed management practices, and adopting new irrigation systems can address challenges like water consumption, agricultural impacts, and infrastructure vulnerability. Future research should accurately assess the effect of these changes in precipitation and temperature on water resources, agriculture, and other infrastructures in the study area to implement effective management measures.

Petrology and organic geochemistry of the Middle Devonian cutinitic liptobioliths from Luquan region, Yunnan Province, China

The majority of Middle Devonian coal samples from Wujing (WJ), Damo (DM), and Batang (BT) areas in the Luquan region of China have cutinite content exceeding 50%, classifying them as typical cutinitic liptobioliths. These coals are notable for their thinly-bedded texture, which allows them to split readily into leaf-like laminae. However, coals from these areas display distinct macroscopic, microscopic, and geochemical features. The split laminae from WJ and DM coals are black and ribbon-like, with those from WJ being notably longer and wider. In contrast, BT coal laminae are irregular, small fragments with golden or brown hues. Correspondingly, the cutinite in WJ coals is predominantly thick-walled, DM coals primarily contain a medium-walled type, and BT coals are characterized by a thin-walled type. Additionally, BT coals are rich in sporinite, with some classified as sporinite-rich durain or sporinitic liptobiolith. Abundant tetracyclic diterpenoids were detected in the maltene fraction of all the coal extracts. The concentration and composition of these diterpenoids are influenced by the content and type of cutinite present in the coals. The presence of tetracyclic diterpenoids, with beyerane, atisane and kaurane skeletons, had already evolved in early land plants. This implies that the precursors of these compounds were likely significant components of the cuticles of early land plants or, at least coexisted alongside plant cuticles. The spore assemblages in coals and the microscopic features of cutinite suggest that the coal-forming plants of the Luquan cutinitic liptobioliths were early land plants, predominantly herbaceous lycopsids, rhyniopsids, Orestovia and Spongiophyton. However, it is important to note that the specific types of these coal-forming plants may vary by areas. This variation leads to the distinctive macroscopic and microscopic characteristics observed in coals from different locations.Cutinitic liptobiolith appears to have been exclusive to the Middle Devonian period, especially during the Givetian. The emergence of this distinct coal type is likely due to the unique structure of Devonian land plants. Specifically, the combination of well-developed cuticles and less developed woody tissues in these early land plants might have played a key role in the formation of cutinitic liptobioliths.

A typology of polished stone axes in the middle Yellow River and their impact on early complex societies

Polished stone axes have long been recognized as essential tools directly related to logging and wood processing in sedentary societies, playing a crucial role in prehistoric people's survival and social production. Their evolution as production tools has been a driving force behind the advancement of society's productive capacities. In this article, information and data on stone axes from the middle Yellow River region are systematically compiled, presenting a typology based on 640 stone axes from 153 sites spanning the Middle Neolithic to the Bronze Age. The main conclusions derived from the study are as follows: (1) Typological study reveals that stone axes can be classified into 7 types. By examining the evolution of these types and their combinations, four distinct phases in the development of stone axes are identified, reaching its peak during the middle stage of Phase 4. (2) The flourishing of the stone axe types originated in the Yangshao period in the Guanzhong Plain. With the development of social complexity and the establishment of the Xia and Shang dynasties after the Longshan period, the center of gravity of stone axe types and assemblages gradually shifted to the Central Plains and the Fen River Valley. Finally, the genealogy spread to the eastern foothills of the Taihang Mountains and declined. (3) The types of stone axes from the late Yangshao period and the middle and late Longshan periods exhibit a clear shift, highlighting their functional differentiation during these periods. (4) The production of stone axes can be categorized into two modes based on the raw stone material used: (a) and (b). The metallization of tools, even during the so-called Bronze Age, experienced significant delays, and it was only during the Yinxu era that bronze axes began to replace some of the stone axes produced in mode (b). (5) The functional differentiation of axes and the transformation of the mode of production have played a role in inducing the emergence of social complexity and expediting its development to some extent.